The Two Headed Worm From Space! It certainly sounds like a good pulpy science fiction story from the 1950s, but in fact, when researchers from Tufts university sent a bunch of flatworms up to the International Space Station (ISS), that's exactly what they wound up with.
On January 10 2015, the researchers sealed up bunch of planarian flatworms (D. japonica) in tubes filled with half water and half air and launched them up to the ISS on a SpaceX resupply mission. What's more, half of the flatworms had parts of their body sliced off. That's not usually a problem for D. japonica, as it has the remarkable ability to regenerate its body in the face of such an event, which is why it's so often studied.
Meanwhile, another group of worms received the same treatment but were left here on Earth.
The results of the study are going to be published in the journal Regeneration tomorrow.
The worms were kept in space for five weeks and then returned for analysis. The most striking finding was that one of the amputated worms grew back a head at each end. What's more, when those heads were sliced off, the worm was able to regenerate each again, showing that its physiology had been permanently changed. "In more than 18 person-years of maintaining a colony of D. japonica that involves more than 15,000 control worms in just the last five years alone, the Tufts researchers have never observed a spontaneous occurrence of double-headedness," says a Tufts report about the research.
In addition to finding the double-headed mutation, the researchers also found that the space worms underwent spontaneous fission in which they split their bodies up to create two or more identical worms. This did not happen with the worms that stayed at home. Furthermore, the astronaut worms (astroworms?) also had a strange reaction to fresh spring water when researchers placed them in it, unlike the worms that stayed behind. They became partially paralyzed, immobile and curled up in their petri dishes before returning to normal in about two hours.
The point of the study was to see if the worms' regeneration patterns were altered while in space, and to see if such findings might have applications to humans as we increasingly set our sights on living and traveling in space.
"As humans transition toward becoming a space-faring species, it is important that we deduce the impact of spaceflight on regenerative health for the sake of medicine and the future of space laboratory research," said Junji Morokuma, first author on the paper.
The researchers are quick to point out though, that the study has a few issues including its small sample size. For one, the worms that stayed on Earth didn't experience exactly the same temperature and pressure fluctuations as the worms that rocketed to the ISS, so it's hard to say what exactly caused the changes. Also, the amputated worms had the procedure done here on Earth and the researchers feel that a space-based slicing would provide them even more information and keep the experiment purer. They plan to correct for these issues in future experiments.
This work joins previous studies carried out at Tufts in which flatworms were engineered to grow the heads of other species and induced to grow two heads by altering their bioelectric currents.
Source: Tufts University
